Contemporary industrial hygiene practices frequently include sampling the air that an industrial worker breathes during his work shift in order to provide information about the contaminants which the worker was exposed to during his work shift. Coal mines and asbestos factories are just a few of the many work sites which are currently under close inspection by hygienists for private and governmental agencies as part of a major effort directed toward reducing the amount of airborne hazardous substances that workers are exposed to at such work sites. Air samples periodically taken in close proximity to workers and accumulated over a given work shift provide a rough indication of the total exposure to airborne substances that such workers suffered. However, such periodic sampling may miss intermittent peak periods of high-level contaminant exposure suffered, for example, when a worker moves about from one area to another.
In accordance with the present invention, a personal-size, air-sampling unit is carried by the worker throughout his entire work shift, and operates continuously to move ambient air samples through a contained test chamber at a substantially constant flow rate. The contaminants accumulated in the test chamber over the period of the work shift can thus be analyzed to provide indication of type and degree of airborne health hazard to which the worker was exposed during his work shift. In addition, the present invention provides immediate audible alarm in response to interruption of air flow and also provides an interrogatable residual alarm to indicate that an interruption of air flow for a sufficiently long period perhaps to invalidate test results occurred some time during the period of operation. In this way, the air-sampling unit carried by a worker throughout his work shift may be turned in after work for subsequent analysis of accumulated contaminants. Requisite treatment or corrective measures may thereafter be administered as required in response to the analysis of such contaminants.